Apparatus and process for accumulating and concentrating heat energy

ABSTRACT

A tortuous working fluid flow path and a high heat energy gaseous compound flow path are aligned in semicontraflow relationship so that the working fluid and gaseous compound interact and become progressively heated and cooled respectively at controlled rates. Working fluid sequentially enters a bank of tubes near the gaseous compound downstream end and flows to a second bank that directly encounters the most intensely hot portion of the flowing gaseous compound. Working fluid departing the second bank is separated into a portion above a given temperature and another portion below a given temperature that is continuously cycled through a recirculating jet pump and the second bank until its temperature also rises above the given temperature. The working fluid portion above the given temperature, which may be the critical temperature of the working fluid, for example, is further heated in a final bank of tubes and eventually discharged in a high quality state to an ultimate use location.

United States Patent [72] Inventor Douglas R. Paxton 3,242.91 1 3/1966 Schroedter 122/406 426 31st St., Newport Beach. Calif. 92660 3,395,678 8/1968 Kochey. Jr .r 122/406 [21 I Applr Nov 788.800 [22] Filed Jan. 3. 1969 [45} Patented Feb. 2, 1971 [54] APPARATUS AND PROCESS FOR ACCUMULATING AND CONCENTRATING HEAT Primary Examiner-Kenneth W. Sprague An0rneyPastoriza & Kelly ABSTRACT: A tortuous working fluid flow path and a high heat energy gaseous compound flow path are aligned in semicontraflow relationship so that the working fluid and gaseous compound interact and become progressively heated and cooled respectively at controlled rates. Working fluid sequentially enters a bank of tubes near the gaseous compound downstream end and flows to a second bank that directly encounters the most intensely hot portion of the flowing gaseous compound. Working fluid departing the second bank is separated into a portion above a given temperature and another portion below a given temperature that is continuously cycled through a recirculating jet pump and the second bank until its temperature also rises above the given temperature. The working fluid portion above the given temperature, which may be the critical temperature of the working fluid, for example, is further heated in a final bank of tubes and eventually discharged in a high quality state to an ultimate use location.

PATENTEDFEB 21911 sum 1 or z INVIZNTOR. DOUGLA S RAY PAXTON lam /PW ATTORNEYS PATENTEU FEB 2 I9?! SHEET 2 [IF 2 FIG.3

INVENTOR. DOUGLAS RAY PA XTO N ATTORNEYS APPARATUS AND PROCESS FOR ACCUMULATING AND CONCENTRATING HEAT ENERGY This invention relates to a heat exchanger and more specifically to a semicontraflow-type heat exchanger capable of supplying high quality working fluid while operating on a start and stop basis.

BACKGROUND OF THE INVENTION It is common practice to employ a contraflow type heat exchanger for transferring heat energy from one flowing fluid to another fluid flowing in an opposite direction. As the hotter fluid becomes progressively cooler, the colder fluid constantly absorbs heat and becomes progressively warmer. Frequently the fluid being heated enters the contraflow heat exchanger as a liquid and departs as a gas.

A serious obstacle that conventional contraflow heat exchangers have been unable to overcome concerns conserving energy and preventing hardware deterioration when the heat exchanger is operated on an intennittent or start and stop basis. When hot gases are being routed in one direction and a fluid for absorbing heat from the gas is being flowed in the opposite direction, the fluid ordinarily exits at amaximum constant temperature. When the fluid flow is abruptly terminated, then the heat energy from the gas can no longer be carried away so available heat energy from the gas boosts the temperature of the now stationary fluid to an extremely high degree where catastrophic results can occur such as destruction of the heat exchanger itself.

Various approaches have been proposed for eliminating this problem such as:

1. immediately injecting cold liquid in the fluid discharge end when the fluid flow is shut off;

2. dumping the hot gas into a cold sump;

3. dumping the extremely hot fluid into a cold sump;

4. providing a huge chamber or tank for the heat absorbing fluid so that the fluid is characterized by a large thermal capacity and therefore can soak in great quantities of heat without appreciable temperature increases; and

5. restricting the thermal capacity of the heat exchanger system to such low temperature limits that anticipated temperature rises by the fluid cannot possibly attain dangerous levels. In addition, these approaches can be combined such as by simultaneously injecting cold liquid and dumping hot gases.

All of the foregoing approaches are unsatisfactory in varying degrees because external systems must be employed or the operational range of the heat exchanger must be restricted to narrow low temperature levels. Another disadvantage inherent in conventional contraflow heat exchangers is their inability to adequately control the temperatures of organic fluids which are very susceptible to thermal breakdown and decomposition.

BRIEF SUMMARY OF THE INVENTION Briefly stated the present invention contemplates a compact, easily operated apparatus with no moving parts, and, a process of for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid. Flow paths for the working fluid and gaseous compound are aligned in semicontraflow relationship so the working fluid becomes progressively heated at a controlled rate while the gaseous compound becomes progressively cooled.

The apparatus includes a first bank of tubes for receiving and preheating the working fluid and a second bank of tubes located further upstream in the gaseous compound flow path than the first bank. Positioned between and arranged in communication with the first and second banks is a recirculation means, such as a recirculating jet pump. The recirculating jet pump is operated by working fluid for recirculating a segment of working fluid discharged from the second bank at a temperature below a given temperature back through the second bank until itexceeds the given temperature.

Working fluid discharged from the second bank and which is above the given temperature is passed to a third bank of tubes that is located physically between the first and second banks and is protected from excessive heating by the recirculation of working fluid through the second bank. Because the recirculating jet pump constantly recirculates working fluid through the second bank. the mass flow rate of working fluid is greater through the second bank than through the first bank and third bank. Before entering the third bank the working fluid is preferably passed through an intermediate bank of tubes located physically between the first and third banks for stabilizing and controlling the working fluid temperature.

Coupled to the recirculating jet pump is a fluid separation chamber for diverting working fluid below the given temperature, which may be the critical temperature of the working fluid for example, back to the recirculating jet pump and diverting working fluid above the given temperature in a direction towards the third bank of tubes. Recirculation is accomplished by a pressure differential established between greater working fluid pressure in a diffuser section of the recirculating jet pump and lower working fluid pressure in the fluid separation chamber. The pressure differential forces working fluid below the given temperature to recirculate through the second bank until its temperature rises above the given temperature. Preferably a spiral is formed on the interior periphery of the fluid separation chamber and working fluid egressing the second bank is tangentially injected against the undersurface of the spiral in order to force the relatively colder working fluid downwardly to the recirculating jet pump.

From a process standpoint the present invention involves the steps of simultaneously flowing a high heat energy gaseous compound and a working fluid along flow paths that intersect in semicontraflow relationship. The working fluid is preheated in a first bank of tubes and then flowed through a chamber to a second bank of tubes. Effluent from the second bank is separated into portions above and below a given temperature. Working fluid above the given temperature is removed from the chamber to a third bank of tubes. Working fluid below the given temperature is recirculated through the chamber and second bank continuously until its temperature rises above said given temperature. The recirculating flow serves to force working fluid through the second bank at a mass flow rate greater than that of the first bank and third bank. At all times the gaseous compound is directed to flow successively into contact with the second bank, third bank, and, then the first bank.

Preferably the temperature of working fluid discharged from the third bank is constantly sensed in order to automatically regulate the mass flow rate of gaseous compound and hence heat quantity entering the system.

BRIEF DESCRIPTION OF THE DRAWINGS The numerous benefits and unique aspects of the present invention will be fully understood when the following detailed description is studied in conjunction with the drawings. in which:

FIG. 1 is a schematic view showing the heat energy accumulator and concentrator system of the present invention;

FIG. 2 is a flow diagram showing how the working fluid and gaseous compound flow paths are arranged in semicontraflow relationship; and,

FIG. 3 is a perspective partially sectional view showing important details of some components of heat energy accumulator and concentrator system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. I, a heat energy accumulator and concentrator system 10 constructed in accordance with the present invention is shown incorporated in one of numerous possible assemblies in which it is important to raise a fluid to high temperature or supercritical temperature without the risk of thermal breakdown. As explained in copending US. Pat. application filed on Oct. l3. l968. and entitled "ENERGY CONVERSION SYSTEM AND PROCESS FOR GENERAT- lNG TORQUE'- the system may be used in various vehicles and other equipment that require generated torque. Typical examples are conventional automobiles and other land vehicles, helicopters. marine vehicles. heavy-duty equipment such as hoists and related article handlers. bulldozers and earth movers, hotel air conditioning and refrigeration systems as well as other related stationary total energy systems.

Heat energy accumulator and concentrator system 10 has an inlet 11 for admitting working fluid at a lower temperature and an exit 12 for discharging the working fluid at a predetermined higher temperature and distributing the working fluid in this state to an ultimate use location' such as a drive mechanism (not shown) arranged to convert thermal energy into mechanical energy. System 10 includes a heat exchanger 13 coupled in fluid communication to a recirculating jet pump 14. Recirculating jet pump 14 is oriented in fluid communication with and coupled to the base of a fluid separator 15. As shall be fully explained, separator 15 operates to divide working fluid into two segments, one segment of which has a temperature below a given temperature while the other fluid segment has a temperature exceeding the given temperature.

Heat energy accumulator and concentrator system 10 is arranged adjacent a heat generating chamber 16 having an exit section 17 through which a high heat energy gaseous compound is distributed to system 10. Heat generating chamber 16 includes an inlet section 18 joined to a mixing chamber 19 that accepts oxidizer such as ambient air from an oxidizer line 20 and fuel from a fuel line 21. The oxidizer and fuel charges issuing through lines 20 and 21 strike or impinge upon one another in mixing chamber 19 where they become sufficiently commingled before being channeled into heat generating chamber 16.

A monitor responsively coupled with mixing chamber 19 and heat energy accumulator and concentrator system 10 includes a sensor 23 for sensing the temperature of the high heat energy gaseous compound flowing through heat generating chamber 16 and, in response to this temperature. regulating the fuel to air ratio.

In ordinary heat exchange systems the amount of heat introduced into the heat exchange system is controlled by changes in pressure. in contrast with this conventional approach another sensor 24 is arranged to sense temperature of the working fluid discharged from heat exchanger 13. in response to this temperature sensed by sensor 24 the mass flow rate of the oxidizer and fuel ingredients and hence the quantity of heat added to the system is thus regulated. Gaseous compound eventually exits through an exhaust line 25.

Referring now to FIG. 2, heat energy accumulator in concentrator system 10 is illustrated in flow diagram or schematic form. Working fluid is transmitted from inlet 11 to a manifold 26 that distributes the working fluid to a bank of tubes A. As shall be fully explained, the working fluid passes sequentially through banks of tubes A, B, C, and finally D. Bank of tubes A includes plural tube clusters 27 that are aligned in rows, in a direction parallel to the flow path of the high heat energy gaseous compound indicated by arrow 28, and in columns aligned perpendicularly to gaseous compound flow path 28. Each tube cluster 27 has three serially aligned individual tubes 29. The important purposes for the particular tubular cluster and individual tube alignment as well as the structural relationships between banks of tubes A, B, C; and D will be fully described as the description of the present invention proceeds.

As employed to explain the present invention the term semicontraflow is intended to mean that while the gaseous compound and working fluid travel in flow paths generally aligned in opposite directions the paths may be aligned in the same directions for relatively short segments. The semicontraflow system of the present invention may also include cross flow segments.

After working fluid has been routed from manifold 26 through tubular clusters 27 it becomes discharged into an exit manifold 30 and routed through a conduit 31 to recirculating jet pump 14. Working fluid issues through a nozzle 32 into recirculating jet pump 14 that is housed in a recirculation chamber 33. Recirculating jet pump 14 includes an entrance throat 34 adjagent nozzle 32, an intermediate mixing section 35, and. a diffuser section 36. Diffuser section 36 communicates with a conduit 37 through which working fluid is flowed to a bank of tubes B.

Bank of tubes B incorporates a plurality of tube clusters 39 each having three individual tubes 40 aligned in parallel with one another. Tubes 40 are shown in clusters 39 merely for comparison purposes so it can be clearly demonstrated that bank B has more fluid inlets and outlets for the working fluid than bank A. After being heated by the gaseous compound to a high energy level the working fluid is passed through an exit manifold .41 to a fluid separation chamber 42 of circular cross section. As indicated by arrow 43 working fluid from manifold 41 is directed tangentially to the undersurface of a spiral 44 incorporated on the interior surface of fluid separation chamber 42. Spiral 44, that is wound through two or more helical turns, functions to assist in diverting working fluid above a given temperature or below a given density to a hot fluid separation zone 45 and working fluid below the given temperature or above a given density to a cold fluid separation zone 46.

While the fluid guided or diverted into zone 45 and 46 may be vapor and liquid respectively, this type of segregation predicated upon differences in fluid state is not necessary and both may be substantially compressible or substantially noncompressible fluids. Intermediate section 47 of recirculation chamber 33, which is a portion of separation chamber 42, is constantly occupied with working fluid. Therefore it can be seen that when centrifugal force drives relatively colder working fluid under spiral 44 it becomes thrust downwardly towards recirculating jet pump 14 so relatively hotter working fluid must rise into hot fluid separation zone 45.

The colder working fluid that is swirled downwardly through recirculation chamber 33 and returned to recirculation jet pump 14, as indicated by arrow 48, is continuously recirculated until its temperature exceeds the predetermined given temperature. Upon this occasion, the particular slug of working fluid will be transmitted through a bypass conduit 49 to manifold 50 associated with bank of tubes C.

The jet of working fluid streaming through nozzle 32 draws fluid from chamber 33 into entrance throat 34. The mass flow ratio of the driving fluid entering throat 34 from nozzle 32 and the driven fluid entering throat 34 from chamber 33 may be for example of the order of one to two. The driving fluid of the jet flow entrains a portion of the driven fluid and increases its acceleration as the two fluids travel through mixing section 35. The combined kinetic energy ,of the two fluids is converted to increase potential energy by reason of distortion in diffuser section 36 so that the fluid pressure at the base of chamber 33 is significantly greater than the pressure of the working fluid in the top of chamber 33. As a consequence, working fluid is pushed through manifold 38 and tubes 40 because of the pressure differential.

One way to increase the percentage of driven fluid entering recirculation jet pump 14 is to increase the distance between the tip of nozzle 32 and location of the smallest diameter of throat 34. The mixing efficiency of the two fluids can be increased by enlarging-the length of mixing section 35 with respect to its diameter. The pressure differential may also be increased by increasing the final exit area of diffuser section 36, or the nozzle orifice .may be reduced to supply more energy by increasing the fluid velocity.

Since individual tubes 29 of bank A constitute only one third of the flow paths that are constituted by individual tubes 40 of bank B it can be understood that, if recirculation jet pump 14 were eliminated the total mass flow rate through banks A and B would be identical but the mass flow rate through individual tubes 29 would be three times greater than that through individual tubes 40. It is important to note at this point that the recirculation jet pump I4 can be modified or adjusted as indicated in the previous paragraph so that not only can the mass flow rate in bank B exceed that of bank A but the individual mass flow rates of tubes can also surpass that of individual tubes 29. The reasons for flowing working fluid at a relatively high mass flow rate through bank B and its individual tubes will be fully explained as the description of the present invention proceeds.

In order to permit fluid separation chamber 42 to divide relatively hot and cold working fluid into zones 45 and 46 respectively, recirculation chamber 33 remains entirely filled with working fluid. When the velocity of working fluid issuing from exit manifold 41 becomes greatly diminished upon entering fluid separation chamber 42, relatively colder working fluid sinks and automatically displaces relatively warmer working fluid which is forced upwardly. It can be seen therefore that if spiral 44 were eliminated, the separation of fluid based on temperature differences could still be effected although not as rapidly as when spiral 44 is employed. Spiral 44 promotes a swifter separation of the relatively hot and cold fluids by accepting working fluid aimed in a tangential direction 43 and retaining the colder fluid beneath its undersurface.

In order to vary the given temperature that distinguishes between the relatively hot and cold working fluid. the width of spiral 44 can be adjusted. For example by widening the width of spiral 44, more working fluid will be routed for recirculation and therefore only working fluid above an increased temperature will be pennitted to flow through conduit 49. Also the jet pump flow rate can be increased.

Working fluid at the desired given temperature is flowed to manifold 50 for distribution through tube clusters 51. As in the case of tube cluster 27 of bank of tubes A, tube clusters 51 are aligned in rows parallel with gaseous compound flow path 28 and in column perpendicular to gaseous compound flow path 28. Individual tubes 52 are arranged in series.

Working fluid is driven to manifold 53 of bank of tubes D for distribution to tube clusters 54. The individual tubes 55 of tube clusters 54 conduct the working fluid into an exit manifold 56 which in turn delivers the working fluid to a pair of exit conduits 57 and 58. Tubes 55 are also shown in clusters 54 merely for comparison purposes so it can be demonstrated that banks B and D each have more working fluid inlets and outlets than banks A and C. Optionally much the same effect would be achieved by employing the same number of fluid inlets and outlets in banks B and D but dimensioning their tubes with larger diameters than those defined by the tubes of banks A and C. It is important to note that the total cross-sectional area of the respective banks is one of the important factors in determining the velocity of working fluid through the individual tubes of the banks.

Exit conduits 57 and 58 may for example deliver the working fluid in its now predetermined optimum state to mechanisms for generating mechanical energy.

The banks of tubes A, B, C, and D are structured to sequentially treat flowing working fluid in such a way that it is gradually transformed to apredetermined high thermal energy state. Bank of tubes A functions primarily to preheat entering working fluid at a steady rate. Bank of tubes B operates to quickly absorb heat from the gaseous compound at a rate sufficient to prevent destruction or melting of individual tubes 40 and 55 while also preventing degradation and decomposition of the working fluid. Bank of tubes C is intended to stabilize the temperature of the working fluid by. either yielding heat energy to or extracting it from the gaseous compound. Bank of tubes D serves to raise the working fluid temperature and furnish working fluid in a high quality state to exit conduits 57 and 58.

Referring now to FIG. 3, working fluid entering heat exchanger 13 through inlet 11 first passes through manifold 26. The working fluid passes through inlet ports 59 into the first individual tubes 29 of three serially aligned tube clusters 27. The tube clusters 27 of bank A are arranged in three columns aligned substantially perpendicular to the gaseous compound flow path 28. Tube clusters 27 are also arranged in plural rows aligned substantially parallel to the gaseous compound flow path. After egressing tube clusters 27 through exit ports 60. the working fluid is routed to conduit 31 that terminates in nozzle 32 which injects working fluid into the throat section of recirculating jet pump 14.

The working fluid flows through bank B and exits by ports 61 to a manifold 41. A stream of working fluid indicated by arrow 43 is injected tangentially from a manifold 41 through a discharge port 62 into fluid separation chamber 42. Discharge port 62 is positioned so that stream 43 impinges upon the undersurface of spiral 44 in order to force colder working fluid against the interior periphery of the fluid separation chamber 42 and downwardly to jet pump 14. As previously mentioned. the colder fluid travels down the outside of chamber 42 beneath spiral 44 and warmer fluid therefore becomes automatically displaced upwardly through the center of chamber 42 and passes outwardly through bypass conduit 49. The colder working fluid is continuously recirculated through bank B by jet pump 14 until it as also exceeds the given temperature.

Working fluid heated to the given temperature flows from bypass conduit 49 to bank C and enters tube clusters 51 through inlet ports 63 arranged in communication with manifold 50. The tube clusters 51 of bank C are aligned in three columns arranged substantially perpendicular to the gaseous compound flow path 28. Tube clusters 51 are also aligned in rows substantially parallel to gaseous compound flow path 28. As in the case of tube clusters 27 of bank A, the tube clusters 51 of each row are arranged in series.

Working fluid passes from manifold 53 to bank D by inlet ports 64. As in the case of tubes 40 of bank B, the tubes 55 of bank D form a single column aligned perpendicularly with gaseous compound flow path 28. In contrast with the individual tube tubes of banks A and C the individual tubes of banks B and D are aligned in parallel with one another. It should be noted that the individual tubes of bank A and bank C are arranged vertically to flow working fluid in alternating upwardly and downwardly patterns. As shown in both FIG. 1 and FIG. 3 the vertically aligned tubes of bank D flow working fluid in a direction opposite to the direction through which the immediately adjacent tubes of bank C flow the working fluid.

The reason for causing the individual tubes of banks A, C, and D to thus periodically or alternately flow working fluid in reverse directions is to achieve a high heat transfer efficiency by substantially uniformly distributing thermal energy of the gaseous compound to the working fluid. If the individual tubes were not arranged to substantially uniformly accept heat from the gaseous compound, then hotter gaseous compound would become concentrated upon particular portions of the individual tubes and gaseous compound exhausted from heat exchanger 13 would then be divided into hotter and colder zones. Inefficiency would be proportional to the disparity of the temperatures in these two zones.

Thus high efficiency is attained by, in essence, arranging the individual tubes so that a high heat transfer capability is maintained throughout the system and the gaseous compound is forced to liberate heat substantially uniformly and exit from heat exchanger 13 without zones of substantial temperature differences. With regard to attaining this desired uniform heat distribution it should be noted that the individual tubes, rather than being aligned vertically, could be aligned horizontally or at any desired inclination.

The individual tubes 55 of bank D are aligned vertically for a purpose to be described. Working fluid heated to the optimum desired temperature flows through exit ports 65 into manifold 56 and outwardly to conduits 57 and 58.

The density, i.e.; number per unit area, of the individual tubes of the various banks may be constant or variable. Their spacing may be tighter or wider for columns than for the rows. One factor dictating the tube density and desirability of incorporating or excluding heat conducting fins 66 on the tubes is predetermined by the impelling power of a blower. for example, used to push the gaseous compound through its flow path 28. As the blower power is increased. the density and percentage of finned tubes may also be increased to maximize heat transfer efficiency.

The tortuous flow path of the working fluid is defined by heat exchanger l3 and recirculating jet pump 14. The flow path 28 of the gaseous compound is defined primarily by the spaces between adjacent individual tubes of banks A. B. C, and D and a surrounding container 67. Container 67 that encloses a portion of heat exchanger 13 is a thin sheet metal duct layered with insulation to prevent escape of heat by radiation or conduction.

Heat exchanger 13 is of general rectangular block configuration and, as can be fully understood now that the structure of the present invention has been fully described, includes no moving parts. Banks B, D, C, and A are arranged successively in an upstream to downstream direction with respect to the gaseous compound flow path 28 so that the temperature of working fluid can be gradually increased as working fluid is moved along its flow path.

OPERATION Keeping the above construction in mind it can be understood how many of the previously described disadvantages of conventional contraflow heat exchangers are overcome or substantially eliminated by the present invention.

For the purpose of explaining its operation, the heat energy accumulator and concentrator system 10 is assumed to be incorporated in an environment where the heat transfer action between the gaseous compound and working fluid is to be at least occasionally started and stopped.

Fresh charges of working fluid entering the system through inlet 11 are preheated in bank A whose individual tubes 29 are arranged to experience a mass flow rate sufficient to prevent the working fluid from stagnating and thermally decomposing.

The most intense heat of the gaseous compound discharged from heat generating chamber 16 is encountered by bank B. Working fluid flowing through individual tubes 40 of bank B, at a relatively high mass flow rate. rapidly absorbs heat from the gaseous compound to prevent components of bank B and bank D from melting or weakening. Relatively high temperature working fluid passing through bank B is separated out at short intervals in order to prevent the working fluid from attaining undesirable high temperatures. The relatively high mass flow rate through bank B, which is greater than that through either banks A, C, or D, is caused by recirculating jet pump 14 that continuously recirculates a segment of working fluid below the given temperature discharged from bank B back through bank B until it also exceeds the given temperature.

Merely physically interposing bank 8 between heat generating chamber 16 and final bank D would adequately protect bank D only during continuous working fluid flow condition. However, this arrangement alone, without recirculation, would fail to prevent overheating and possible destruction during sudden termination of working fluid flow through exit conduits 57 and S8.

The physical integrity of bank D is preserved during intermittent or stop and start situations by recirculating jet pump 14. When for example exit conduits 57 and 58 are shut off a sizeable slug of working fluid will still be continuously cycled through jet pump 14 and bank B to withdraw heat from the gaseous compound that still -unpreventably is impinging against bank B with undiminished heat content. Recirculation of this slug of working fluid continues due partially to its inertia and momentum, the lingering pressure differential which sustains the pumping action, and, convection currents developed within the working fluid that establish a thermal siphon effect for enhancing the pumping action. Thus the recirculation activity is sustained for a period of time sufficient to shut off or at least safely diminish the flow of intensely hot gaseous compound. It is contemplated that when substantial recirculation activity comes to a natural halt, sufficient time will have elapsed to reduce the heat content of the gaseous compound below the danger level. By distributing heat evenly from the gaseous compound throughout a large segment of the working fluid. this available heat in the gaseous compound is prevented from being concentrated upon a relatively small portion of working fluid at the instant that discharge is stopped.

Some organic fluids must be heated at a more gradual rate when below .their critical temperatures than when above their critical temperatures or else thermal breakdown will result. When these organic fluids are forced to absorb heat at a harmfully high rate, under conditions where local hot spots are engendered, they tend to break down into undesirable constituents incapable of being reunited. Some of the constituents fail to vaporize while others fail to condense and some constituents exist as solids that are deleterious to the system efficiency. These constituents may also form acids capable of attacking and destroying various container materials.

A related problem with some organic fluids is that portions above the critical temperature cannot be heated to high temperatures while in contact with portions below the critical temperature or else thermal breakdown may occur in the fluid of subcritical temperature. Supercritical temperature fluid must be separated from the subcritical temperature fluid before its temperature is raised to a higher level.

For purposes of explaining the operation of the present invention it is assumed that the working fluid is one of these organic fluids prone to thermal breakdown under conditions outlined above. Fluid separation chamber 42, in this situation. would be arranged to divert working fluid above critical temperature to bypass conduit 49 in order to separate it from relatively cooler working fluid below the critical temperature. As has been previously explained the working fluid temperature is gradually raised at a controlled rate while flow is occuring through banks A and B and is prevented from sharply rising when flow is abruptly stopped due to the recirculating action developed in part by jet pump 14.

Inasmuch as bank B includes more fluid inlets and outlets than bank A and its individual tubes 40 are arranged in parallel to define much shorter flow paths than those defined by individual tubes 29 of bank A, it can be understood that working fluid passing through bank B is relatively quickly transmitted to fluid separation chamber 42 and is prevented from becoming heated to a dangerous level. Thus bank B is structured so that working fluid recirculated therethrough is exposed to the gaseous compound for a sufficient duration to acquire significant heat but its flow paths are sufficiently short so that the working fluid has frequent opportunities to escape to fluid separation chamber 42. The working fluid is permitted to escape from separation chamber 42 through bypass conduit 49 before it reaches a temperature which would tend to cause decomposition of the working fluid still below critical temperature. I

Working fluid diverted through bypass conduit 49jenters bank C where it encounters gaseous compound with diminished heat content. Initially working fluid flowing through bank C may liberate heat to the gaseous compound but eventually it absorbs heat from the gaseous compound at a stable and controlled rate. The flow paths are longer through individual tubes 52 of bank Cthan through individual tubes 40 of bank B so that the working fluid has an opportunity to absorb considerable thermal energy from the gaseous compound without serious risk of stagnation. The risk of stagnation and decomposition is minimized in bank C because its individual tubes 52 are arranged to experience a relatively high mass flow rate.

The individual tubes 55 of final bank D are arranged in parallel like the individual tubes 40 of bank B. Due to the previously mentioned recirculation action the mass flow rate through bank B and its individual tubes is much greater than the mass flow rate through bank I) and its individual tubes. Since it is important to supply working fluid of high quality at a substantially constant temperature through exit conduits 57 and 58. bank D operates to assure that this objective is accomplished. While even ordinary contraflow heat exchangers are capable of furnishing fluid at a relatively constant temperature during continuous flow situations they are incapable of doing so economically when flow is commenced from a stopped or stalled condition.

The individual tubes 55 are vertically aligned to lift working fluid and minimize the tendency of discharging relatively higher density working fluid from bank D to exit conduits 57 and 58. By this structural arrangement the colder and thus poorer quality working fluid tends to gravitationally settle near the bottom sections of individual tubes 55 so only warmer, high quality working fluid rises to the top near the exit ports. Therefore when exit conduits 57 and 58 are opened the relatively high temperature, low density, high quality working fluid flows outwardly. Since individual tubes 55 are arranged in parallel the velocity of working fluid in tubes 55 will be maintained at a sufficiently low level so that it will be prevented from lifting the poorer quality high density fluid. Eventually, upon resumed flow of the hot gaseous compound this poorer quality working fluid will absorb enough heat to attain its ideal operating temperature and experience a drop in density to the point where it will rise in the stream of high quality fluid and be discharged through exit conduits 57 and 58.

As previously mentioned the quantity of thermal energy added to the system by the gaseous compound is controlled, not by sensing differences in pressure as is the customary manner, but by arranging sensor 24 to constantly sense the temperature of working fluid discharged from heat exchanger 13. in response to the temperature sensed by sensor 24 the mass flow rate of oxidizer and fuel ingredients flowing into heat generating chamber 16 is automatically regulated to match the demand by system 10.

It can be seen now that the gaseous compound flow path and working fluid flow path within the heat energy accumulator and concentrator system are arranged in semicontraflow relationship in such a manner that working fluid is progressively heated while gaseous compound is progressively cooled.

From the foregoing it will be evident that the present invention has provided an apparatus and process for accumulating and concentrating heat energy in which all of the various advantages are fully realized.

1. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising:

a. a heat exchanger;

b. means including the heat exchanger for defining a tortuous flow path of for working fluid;

c. means including the heat exchanger defining the flow path for high heat energy gaseous compound, the flow paths being aligned in semicontraflow relationship so the gaseous compound can transfer heat to the working fluid;

d. a recirculating jet pump operated by the working fluid for recirculating a segment of working fluid through a portion of the working fluid flow path, the pump including an entrance throat, an intermediate mixing section, and a diffuser section;

e. a first working fluid flow path segment positioned to in- I ject working fluid into the entrance throat;

f. a fluid separation chamber coupled at its base to the recirculating jet pump for diverting working fluid below a given temperature back to the recirculating jet pump, and, diverting working fluid above said given temperature in a direction away'from the recirculating jet pump; and

g. a second working fluid flow path segment for passing working fluid to the fluid separation chamber, the second segment being located downstream of the first segment;

wherein a pressure differential isestablished between greater working fluid pressure in the diffuser section and lower working fluid pressure in the fluid separation chamber to force working fluid below said given temperature to recirculate until its temperature rises above said given temperature.

2. The structure according to claim 1 including;

a spiral formed on the interior periphery of the fluid separation chamber, the second working fluid flow path segment being oriented to tangentially inject a stream of working fluid against the undersurface of the spiral in order to force colder working fluid downwardly to the recirculating jet pump.

3. The structure according to claim 2, including:

a bypass conduit connected to the top portion of the fluid separation chamber for conducting away diverted working fluid whose temperature is above said given temperature.

4. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising:

a. means defining a flow path for a high heat energy gaseous compound;

b. a first bank of tubes for receiving and preheating working fluid and having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path, the first bank of tubes including at least two columns with adjacent tube clusters of the different columns constituting rows aligned substantially parallel to the gaseous compound flow path, the clusters of each row being aligned in series;

c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path;

d. recirculating means operated by the working fluid for recirculating a segment of working fluid discharged from the second bank back through the second bank;

e. an exit conduit for discharging working fluid; and

f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path.

5. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising:

a. means defining a flow path for -high heat energy gaseous compound;

b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path;

c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous com pound flow path;

d. recirculating means operated by the working fluid for recirculating a segment of working fluid discharged from the second bank back through the second bank;

e. an exit conduit for discharging working fluid;

f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; and

g. an intermediate bank of tubes in communication with the second bank at its upstream end and in communication with the third bank at its downstream end for stabilizing and controlling the working fluid temperature, the intermediate bank having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path.

6. The structure according to claim 5, wherein:

the intermediate bank of tubes includes at least two columns with adjacent tube clusters of different columns constituting rows aligned substantially parallel to the gaseous compound flow path. the tube clusters of each row being arranged in series.

7. The structure according to claim 5. wherein:

the individual tubes of the first, second, third and intermediate banks are substantially equivalent in length and cross section and at least some of the individual tubes carry externally mounted heat conducting fins.

8. A heat energy system for accumulating a high energy gaseous compound and concentrating it upon a working fluid the system comprising:

a. means defining a flow path for a high heat energy gaseous compound;

b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path;

c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path;

d. recirculating means operated by the working fluid for recirculating a segment of working fluid discharged from the second bank back through the second bank;

e. an exit conduit for discharging working fluid; and

f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path;

wherein, the second, third and first banks of tubes are arranged successively in an upstream to downstream direction within the gaseous compound flow path so the temperature of the working fluid can be gradually increased along its flow path.

9. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid whose flow paths are arranged in semicontraflow relationship, the system comprising:

a. means defining a flow path for the high heat energy gaseous compound;

b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes that intersect the gaseous compound flow path;

c. a second bank of tubes having a column of individual tubes that intersect the gaseous compound flow path;

d. recirculating means in communication with and located between the first bank and second bank for recirculating a segment of working fluid discharged from the second bank back through the second bank; and

e. a third bank of tubes having a column of individual tubes that intersect the gaseous compound flow path, wherein the banks of tubes are arranged so that gaseous compound is forced to successively contact the second bank, third bank, and first bank to become progressively cooled as the working fluid become progressively heated.

10. The structure according to claim 9, including:

an intermediate bank of tubes located physically between the first and third banks for stabilizing and controlling the working fluid temperature.

11. The structure according to claim 10, wherein:

the individual tubes of the second bank and third bank are arranged in parallel and the individual tubes of the first the second bank and third bank have more working fluid inlets and outlets than the first bank and intermediate bank. 14. A heat energy system for accumulating a high heat encrgy gaseous compound and concentrating it upon a working fluid, the system comprising:

a. means defining a flow path for a high heat energy gaseous compound;

b. plural banks of tubes aligned along the gaseous compound flow path for conducting working fluid, each bank having individual tubes that intersect the gaseous compound flow path; and

. a final bank of tubes included in said plural banks having a cross-sectional area greater than at least one other of said plural banks, the final bank having individual tubes aligned vertically to lift working fluid and minimize the tendency of discharging relatively higher density working fluid.

15. A process of concentrating heat energy contained in a gaseous compound upon a working fluid, the process comprising the steps of:

a. simultaneously flowing a high heat energy gaseous compound and a working fluid along semicontraflow paths;

b. preheating the working fluid in a first bank of tubes;

c. flowing the working fluid through a chamber to a second bank of tubes;

d. separating working fluid effluent from the second bank into portions above and below a given temperature;

e. removing working fluid above the given temperature from the chamber to a third bank of tubes positioned between the first and second banks;

f. recirculating the working fluid below said given temperature through said chamber and second bank until its temperature rises above said given temperature, the recirculation serving to force working fluid to flow at a greater mass flow rate through the second bank than through the first bank and third bank; and

g. directing the gaseous compound to flow successively in contact with the second bank, third bank and then first bank.

16. The process according to claim 15, wherein;

recirculation of the working fluid below said given temperature is accomplished with a pumping action.

17. The process according to claim 15, wherein:

said given temperature is the critical temperature of the working fluid.

18. The process according to claim 17, including the step of:

flowing working fluid above critical temperature through an intermediate bank between the second bank and third bank in order to gradually increase its temperature to a level below the working fluid thermal breakdown temperature.

19. The process according to claim 15, including the step of:

lifting the working fluid vertically through the third bank to minimize the tendency of discharging relatively higher density working fluid from the third bank.

20. The process according to claim 15, including the step of:

constantly sensing the temperature of working fluid discharged from the third bank and automatically regulating the mass flow rate of the gaseous compound. 

1. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising: a. a heat exchanger; b. means including the heat exchanger for defining a tortuous flow path of for working fluid; c. means including the heat exchanger defining the flow path for high heat energy gaseous compound, the flow paths being aligned in semicontraflow relationship so the gaseous compound can transfer heat to the working fluid; d. a recirculating jet pump operating by the working fluid for recirculating a segment of working fluid through a portion of the working fluid flow path, the pump including an entrance throat, an intermediate mixing section, and a diffuser section; e. a first working fluid flow path segment positioned to inject working fluid into the entrance throat; f. a fluid separation chamber coupled at its base to the recirculating jet pump for diverting working fluid below a given temperature back to the recirculating jet pump, and, diverting working fluid above said given temperature in a direction away form the recirculating jet pump; g. a second working fluid flow path segment for passing working fluid to the fluid separation chamber, the second chamber segment being located downstream of the first segment; and h. wherein a pressure differential is established between greater working fluid pressure in the diffuser section and lower working fluid pressure in the fluid separation chamber to force working fluid below said given temperature to recirculate until its temperature rises above said given temperature.
 2. The structure according to claim 1 including; a spiral formed on the interior periphery of the fluid separation chamber, the second working fluid flow path segment being oriented to tangentially inject a stream of working fluid against the undersurface of the spiral in order to force coldeR working fluid downwardly to the recirculating jet pump.
 2. simultaneously flowing a high heat energy gaseous compound and working fluid along semicontraflow paths; b. preheating the working fluid in a first bank of tubes; c. flowing the working fluid through a chamber to a second bank of tubeS; d. separating working fluid effluent from the second bank into portions above and below a given temperature; e. removing working fluid above the given temperature from the chamber to a third bank of tubes positioned between the first and second banks; f. recirculating the working fluid below said given temperature through said chamber and second bank until its temperature through said chamber and second bank until its temperature rises above said given temperature, the recirculation serving to force working fluid to flow at a greater mass flow rate through the second bank than through the first bank and third bank; and g. directing the gaseous compound to flow successively in contact with the second bank, third bank and then first bank.
 3. The structure according to claim 2, including: a bypass conduit connected to the top portion of the fluid separation chamber for conducting away diverted working fluid whose temperature is above said given temperature.
 4. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising: a. means defining a flow path for a high heat energy gaseous compound; b. a first bank of tubes for receiving and preheating working fluid and having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path, the first bank of tubes including at least two columns with adjacent tube clusters of the different columns constituting rows aligned substantially parallel to the gaseous compound flow path, the clusters of each row being aligned in series; c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; d. recirculating means by the working fluid for recirculating a segment of working fluid discharged from the second bank back through the second bank; e. an exit conduit for discharging working fluid; and f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that line intersects the gaseous compound flow path.
 5. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising: a. means defining a flow path for high heat energy gaseous compound; intersects the b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path; c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; d. recirculating means operated by the working fluid for recirculating a segment of working fluid discharged from the second bank back through second bank; e. an exit conduit for discharging working fluid; f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; and g. an intermediate bank of tubes in communication with the second bank at its upstream end and in communication with the third bank at its downstream end for stabilizing and controlling the working fluid temperature, the intermediate bank having individual tubes serially aligned in a column of tube clusters that intersects the gaseous compound flow path.
 6. The structure according to claim 5, wherein: the intermediate bank of tubes includes at least two columns with adjacent tube clusters of different columns constituting rows aligned substantially parallel to the gaseous compound flow path, the tube clusters of each row being arranged in series.
 7. The structure according to claim 5, wherein: the individual tubes of the first, second, third and intermediate banks are substantially equivalent in length and cross section and at least some of the individual tubes carry externally mounted heat conducting fins.
 8. A heat energy system for accumulating a high energy gaseous compound and concentrating it upon a working fluid the system comprising: a. means defining a flow path for a high heat energy gaseous compound; b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes serially alIgned in a column of tube clusters that intersects the gaseous compound flow path; c. a second bank of tubes in communication with the first bank, the second bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; d. recirculating means operated by the working fluid for recirculating a segment of working fluid discharged from the second bank back through the second bank; e. an exit conduit for discharging working fluid; and f. a third bank of tubes in communication with the second bank at its upstream end and in communication with the exit conduit at its downstream end, the third bank having a column of individual tubes aligned in parallel that intersects the gaseous compound flow path; wherein, the second, third and first banks of tubes are arranged successively in an upstream to downstream direction within the gaseous compound flow path so the temperature of the working fluid can be gradually increased along its flow path.
 9. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid whose flow paths are arranged in semicontraflow relationship, the system comprising: a. a men means defining a flow path for the high heat energy gaseous compound; b. a first bank of tubes for receiving and preheating working fluid, the first bank having individual tubes that intersect the gaseous compound flow path; c. a second bank of tubes having a column of individual tubes that intersect the gaseous compound flow path; d. recirculating means in communication with and located between the first bank and second bank for recirculating a segment of working fluid discharged from the second bank back through the second bank; and e. a third bank of tubes having a column of individual tubes that intersect the gaseous compound flow path, wherein the banks of tubes are arranged so that gaseous compound is forced to successively contact the second bank, third bank, and first bank to become progressively cooled at the working fluid become progressively heated.
 10. The structure according to claim 9, including: an intermediate bank of tubes located physically between the first and third banks for stabilizing and controlling the working fluid temperature.
 11. The structure according to claim 10, wherein: the individual tubes of the second bank and third bank are arranged in parallel and the individual tubes of the first bank and intermediate bank are serially aligned in multiple tube clusters.
 12. The structure according to claim 10, wherein: the second bank and third bank have greater flow cross-sectional areas than the first bank and intermediate bank.
 13. The structure according to claim 12, wherein: the second bank and third bank have more working fluid inlets and outlets than the first bank and intermediate bank.
 14. A heat energy system for accumulating a high heat energy gaseous compound and concentrating it upon a working fluid, the system comprising: a. means defining a flow path for a high heat energy gaseous compound; b. plural banks of tubes aligned along the gaseous compound flow path for conducting working fluid, each bank having individual tubes that intersect the gaseous compound flow path; and c. a final bank of tubes included in said plural banks having a cross-sectional area greater than at least one other of said plural banks, the final bank having individual tubes aligned vertically to lift working fluid and minimize the tendency of discharging relatively higher density working fluid.
 15. A process of concentrating heat energy contained in a gaseous compound upon a working fluid, the process comprising the steps of:
 16. The process according to claim 15, wherein; recirculation of the working fluid below said given temperature is accomplished with a pumping action.
 17. The process according to claim 15, wherein: said given temperature is the critical temperature of the working fluid.
 18. The process according to claim 17, including the step of: flowing working fluid above critical temperature through an intermediate bank between the second bank and third bank in order to gradually increase its temperature to a level below the working fluid thermal breakdown temperature.
 19. The process according to claim 15, including the step of: lifting the working fluid vertically through the third bank to minimize the tendency of discharging relatively higher density working fluid from the third bank.
 20. The process according to claim 15, including the step of: constantly sensing the temperature of working fluid discharged from the third bank and automatically regulating the mass flow rate of the gaseous compound. 